Grinding wheel truing mechanism



NOV. 20, 1951 w TANCRED 2,575,984

GRINDING WHEEL TRUING MECHANISM Filed Feb. 4, 1946 2 Sl-iEETS-Sl-IEE'i 1 Nev.20, 1951 w AN D' 2,575,984

GRINDI'NG WHEEL TRUING MECHANISM Filed Feb. 4, 1946 2 SHEETS-SHEET 2.

IN V EN TOR.

spondingly proper form.

Patented Nov. 20, 1951 UNITED STATES PATENT OFFICE 2,575,984 V I I GRINDING WHEEL 'rnuino MECHAPEIS M William L. Tancredg-Springfield, Vt., assignor to Jones & Lamson Machine Company, Springer field, 'Vt., aucorporation of Vermont Application February 4, m c-serial No. 645393 6 Claims. (c1. 125+1 1 This invention relates to mechanism fortruin grinding wheels and more particularly for truing Still another object is to'provide means for dressing thread or other forms ofany desired contour by the use of a screw Jcam of thecorre- For a more complete understanding of this invention, reference may be had torthe accompanying drawings in which 1 r I I Figure 1 is a top plan view of mechanismembodying the invention. M a i I Figure 2 is a side elevation ofthe same;

Figure 3 is a rear elevationofthesame; I 3

Figure 4 is a developed peripheral view-of. the

cam. I I Figure 5 is asectional view on line 5- -l-5-o'f Figure 4. I I l Referring to Figures 1, 2 and 3, the mechanism comprises a bed I which, if desired, may beaportion of a thread grinding machine. Thisubed I is provided with a pairof upstanding posts 2 spaced apart and having bearings 3- at their upper ends for the journaled reception of a shaft 4 to which the grinding wheel 5 is securedw-The shaft 4 may have suitable means for rotating it, a belt pulley 6 being shown for this purposein Figure 1. This belt pulley may be driven from any suitable drive means such as an electric motor (not shown) I g The bed I has slidably mounted thereon a support ii], this support being movable transverse to the axis of the shaft 4. It is normally biased toward this axis as by a spring I I one end of which is engaged with a loop I2 on the support It, and the other end is engaged with a fixed portion I3 of the bed I. The limitof such motion-is determined by the vengagement therewith of a threaded feed screw I4, this being threaded through an upright portion I5'of the support I0. This screw is journaled in a bearing I6 secured to the bed I as by one or more screws I l, andis arranged to be turned periodically in feed direction as by ratchet mechanism shown best in Figure 3. t t

The screw I4-has secured toits-outerendya ratchet wheel 20 against which bears a locking pawl 21 and a dog 22 pivotally carriedb'y-a rock arm 23 -journa1ed on the feedscrewi I4 'outwardly the support ID. This can 54.

of the bearing I6; Aspring 24 engaging atone endwith a portion of the dog 22 and at its other end with a fixed pin 250n the bed I, tends to hold the dog 22 in engagement with the ratchet wheel andthe arm 23 at its left hand limitwof motion as determined by the adjustable stop screw 33.. The holding pawl 2| may engagethe wheel by gravity to prevent retracting. motion thereof when the arm 23 is-rocked in retracting direction. This arm 23 is connected through a link 28 with the core 29 ofithe solenoid 3B. Since the movement of the core 29 inwardly is fixed, adjustment of the limit of back motion of the arm 23 adjusts the amount of turning ofthe ratchet wheel 20 atfleach actuation thereof,

The support I0 has pivoted thereto, as on the shaft 35, a track member 36 which has a pair of ways 31 and 38 securedto its upper face, these ways having V grooves 39 therein for the reception of bearing balls 40 which support between them a carriage 4|, this carriage being guided between the ways 31 and 38 for motion parallel to the 'axes of the shaft 4 andofvthe pivot shaft135. The angular position. of the trackim'ember 36is partly determined by a spring .45 upon which it-issupported, this spring resting upon avertically adjustable abutment or pocket 50 The vertical adjustment may be produced by turning the abutment aboutits axisso-as to determine the extentof threadingof a shank portion 5i thereof in a threaded opening 52 in spring also holds a follower or tracer 51 fixed to anarm 53-projectingfrom the carriage 4| into engagement with a helical This cam is carried by a shaft '55 mounted in bearings 56 and arranged parallel to the wheel shaft 4;

The shaft 551s provided with suitable means for rotating it and as shown this means comprises a worm wheel '60 fixed thereto with which meshesa worm 6| carried by a shaft 62 j'our naled in bearing arms 6! spaced to'permit the worm 61 to .be positionedtherebetween. The shaft 62 is coupled; through an internally splined sleeve 63 with the externally splined portion 64 of a shaft 65, which is driven by a small motor -66 'shown as :mountedio'n fone'of the posts- 2'. This motor 66 is of the reversing type so them may-rotate the helical cam 54 in either direction. This helical camhas a helical cam face so fashioned as to cause the follower Elto rock about the axis of the pivot shaft 35 and at the sametime to cause the carriageflgto move par-- allel to the axes-- of the grinding med ans-the helical cam, the spring 45 holding the follower in contact with the base of the cam groove.

The carriage 4| has a post portion upon which may bemounted for angular adjustment the truing tool secured by screw 750. As shown this tool is carried by a disk 16 adjustably about a central pivot 11 and clamped in adjusted position. by means of the screws '14 passing through arcuate slots =19 in" the disk '16 and threaded into a securing block 18 adjustable along the T shaped way 80 0f the carriage 4i and clamped in position as by screwsfll. The helical groove in the helical cam is shaped in accordance with the desired contours;of,the several ribs of the grinding wheel, not onlyprog-ressingaxially'but varying in depth, as shown in F-igure 5,'so

that as the cam is rotated, the ;tool,.wl ile@,traversing' lengthwise of theface 'QftheIgrinding wheel, also moves in andput, to true thegrinding wheel to the desired multiple rib contour. As

zshowngtheigrooveof the helical cammisso formed taste-true the wheel inna multiplicity of ridges -each; shapecl to cut asteepfaced thread in work groundlthereby, though it will be evidentthatby .;using-1a.cam having a different groovehcontour, (the grinding wheel may be -truedto a correspond- :ing;.c onto,ur in eachof its ridgesland that this .contour may be uniform. for each ,ridge or may J18 varied from: one toanotheras desired.

, .Means are provided by which when the truing ,device has, traversed .the wheel inone direction, ,it lwillfbe reversed. to traverse it in .the opposite :directionand atthe same timeit will be fed into the wheel. To this end, at eachend. of thevcarriagetravel are positioned stop switches indicat- ,-.ed at, 85. and when either of these stop. switches ,isengaglid,itreversesthe.direction of travel of jtheglielicalcamand itmayalso be caused to acetuate thefeed-solenoid 3B toturn the feed screw :As shownlbest in EigureB, the switches 85 are norm ally open, switches, uandlwhen closed 1 by im- ;pingement thereon ofthe carriage, a. circuit is closed which. notonlymeverses the motor, 6B, but a oenergizesthemsolenoidziillcto produce a.feeding impulse. when ,the right hand switch Alas lli wfi hin F g r .3,ci s,r clo sed,, a circuit is sedfr m heli e,tfiilithrouehthe,leadfllll I, the l harm. .1312 lead U1 and. lMulqoking s le- ,Encreizatio ofethe so enoi J95 l f a lo ki p n if. m ne notc -Ji nax n o l ve 712 Tit/high th e o moved o t ce tmncei o b t e 'a' n apa qft enie i esnrioe l 1. This allows the circuit from the line lml through thei 'sw'itch arms" fill to be broken, thus opening "the c'ircuit tothe'r'notor 66 throughtheleads iii, motor 56, leads 122, from the line I01. The ener'giz'ationof 'thsolenoid ilfl' acts to pullth e arm 23 to the right to produce a feed turn to feed screwl l'. The opening of'the switch I20 stops the rotation of' the motor 65 and ends the dressing-cycle {with the 'truing tool-inthe dotted line position 15a beyond the width of the grinding wheel where'the righthand switch 85-has been closed. When a second cycle is desired, thelever H2 is .movedin the opposite; directionfrom its previous ,pQsition-l-to; close the switch at I25, by engagement on onearm thereof of a portion of the lever I I2. fIFhis energizesthe motor 66; inthe reverse direction, from the line ll!!! through lead 126, motor Q6, lead I21, switch l 25, lead I23 and back to the line [01. This startsthe motor 66 in the reverse di tin Wit ,iee err ae m vies ioth l t those skilled in the art that various changes and modifications may be made without departing from its spirit or scope.

I claim: l. In combination, a base, a work supporting ,shaftrotatably mounted in the base, a rotatable helical cami'nount'ed on the base and arranged tinspaced parallel relation with respect to the work supporting shaft; a support pivotally mounted on theibase andarranged between the shaft andthe cam, .acarriage-movably mounted on said sup port reimburse parallel to the axes of the shaft and cam, a follower carried by said carriage and engaging said cam, a tool carried by said carriage in position tooperate on a work piece carried by saidwork supporting shaft, yieldable means holding-izthe. support in angular position to maintain the follower against said .cam, andmeans opera- .tively. connectedito said cam forrotating the same.

2. In combination a base, a work supporting shaft jourhaled in said base,- ahelioal cam, means s pporting said camifor' rotation aboutan axis substantially parallel to the axis of rotation of said shaft, a support pivoted on an axis substan- LtiallyLparallel to said cam axis, a carriage movably :mounted on said. supportiormo'tion parallel. to said axis, a followerx'zarried by said carriageand engaging with said cam, a tool carried by said carriage in position to operate on a work piece carried by said work-supporting means, yielding means holding said support in angular position for said follower ,tol'engage said cam, means operatively connected to: said'cam forfrotating saidcamlandmeansoperatively connected to saidsupportfor periodically feeding said support toward the work piece.

3. In combination with .a work piece holding means mounted for rotation about an axis, of .a supportmounted formotion toward. and from said workeholdingmeans; a: track member pivoted ,to said support .on an axis substantially parallel to said; rotational axis, a carriage movably mounted onisaid trackmember; for. motion parallel toesaid axes, a tool carried ,by saidrcarriage in position toloperate ;upon :work'. carried by said work-hold- .ing means-a helical. cam carried by said support for rotation, about an axissubstantially parallel to t he;h.01ding means axis,:a followerlengaging saidycam'andgcarried bysaid carriage, means operatively connected thereto and yieldingly holdinggsaidtrack member in angular .position about itsaxis to press said follower against said cam, .amitmeans operativelyiconnected thereto for retating said cam.

,4 In combination, with. a ,work piece holding means muntedfor rotation about an axis, of a SUPPQI'ILHIOuIlllGd .for. motion toward and, from said workeholding meansa track member-pivoted to said;support on anaxis substantially parv illel to said rotational axis, a carriage movably mounted on s a'id trackmemberforjmotion parallel-to saidaxes, a: tool carried by said carriage in position to operateupon work carried bysaid work-holding, means, a helical cam carried by said support for rotation about'an axis substantially parallel-to the holding means axis, a follower engaging said cam and carried by said carriage, means operatively connected thereto end isld n e dins sa d t a k me ber in angular position about its axis to press said follower against said cam, means operatively connected thereto for rotating said cam, and means operatively connected thereto for feeding said support with respect to said Work-holding means.

5. In combination with a work piece holding means mounted for rotation about an axis, of a support mounted for motion toward and from said work-holding means, a track member pivoted to said support on an axis substantially parallel to said rotational axis, a carriage movably mounted on said track member for motion parallel to said axes, a tool carried by said carriage in position to operate upon work carried by said work-holding means, a helical cam carried by said support for rotation about an axis substantially parallel to the holding means axis, a follower engaging said cam and carried by said carriage, means operatively connected thereto and yieldingly holding said track member in angular position about its axis to press said follower against said cam, means operatively connected thereto for rotating said cam, and means operatively connected to said rotating means for automatically reversing the direction of rotation of said cam when said carriage reaches predetermined limits of motion on said track member.

6. In combination with a work piece holding means mounted for rotation about an axis, of a support mounted for motion toward and from said work-holding means, a track member pivoted to said support on an axis substantially parallel to said rotational axis, a carriage movably mounted on said track member for motion parallel to said axes, a tool carried by said carriage in position to operate upon work carried by said work-holding means, a helical cam carried by said support for rotation about an axis substantially parallel to the holding means axis, a follower engaging said cam carried by said carriage, means operatively connected thereto yieldingly holding said track member in angular position about its axis to press said follower against said cam, means operatively connected thereto for rotating said cam, means'operatively connected thereto for feeding said support with respect to said workholding means, and means operatively connected to said rotating means for automatically reversing the direction of rotation of said cam when said carriage reaches predetermined limits of motion on said track member and for actuating said feeding means by determined amounts.

WILLIAM L. TANCRED.

REFERENEES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 845,305 Liebert Feb. 26, 1907 1,623,113 Hanson Apr. 5, 1927 1,687,260 Ross Oct. 9, 1928 1,937,961 Hutchinson Dec. 5, 1933 2,228,902 Allen Jan. 14, 1941 FOREIGN PATENTS Number Country Date 97,882 Austria Sept. 25, 1924 

